Coastal LandscapesAims:• To know how the coastline is shaped.• To understand the different types of wave and their characteristics.• To be able to explain the different types of weathering, erosion and mass-movement.
The coast is under attack through a variety of processes:• Erosion• Weathering• Mass-movement
Weathering or Mass-Movement? Chemical Weathering Slumping Biological Weathering What other forms are there?
CorrosionHydraulic action Processes of erosion Attrition Abrasion
AttritionMaterial carried by the waves bump into each other and soare smoothed and broken down into smaller particles.Hydraulic ActionThis process involves the force of water against the coast.The waves enter cracks (faults) in the coastline andcompress the air within the crack. When the waveretreats, the air in the crack expands quickly causing aminor explosion. This process is repeated continuously.CorrosionThis is the chemical action of sea water. The acids in thesalt water slowly dissolve rocks on the coast. Limestoneand chalk are particularly prone to this process.Abrasion/CorrasionThis is the process by which the coast is worn down bymaterial carried by the waves. Waves throw theseparticles against the rock, sometimes at high velocity.
Weathering is the natural breakdown of rocks at the earth’s surface.Using Geographical Foundations pgs 57- 58.Task:1. Describe and explain the 3 main types of weathering.2. What is mass-movement?3. What are the different types?
What affects the rate ofcoastal erosion?Waves are the main agents of erosion at coastlines. Wave action and power depends upon different factors.What factors affect waves?
Why are waves generally larger in the south west than in the south east?Wave energy depends on thefetch, the strength of thewind and the length of timeover which the wind hasblown.fetch = the distance overwhich the wind has blownComplete Activity 1 on pg 57.
Waves can either be… Destructive waves Constructive wavesTasks:1. Copy the diagrams of figure 1 and figure 2 on page 56.2. Describe how these waves are different and add a summary using page 57.
Breaking waves cause twomovements:• Swash moves up the beach• Backwash moves straight down the beach
Swash and backwash Backwash Swash Remember: Backwash is always at right angles to the beach!
Constructive Waves Spilling Breaker Powerful Swash h ackwasW eak B DEPOSITS MATERIAL
Destructive Waves Crashing breaker sh Weak swaPowerful Backwash ERODES MATERIAL